High definition heater system having a fluid medium

ABSTRACT

A thermal system includes a base member, a two-phase fluid, a tuning heater, and a chuck. The base member includes at least one fluid passageway. The two-phase fluid is disposed within the fluid passageway. A pressure of the two-phase fluid is controlled such that the two-phase fluid provides at least one of heating and cooling to the base member. The tuning heater is secured to the base member. The chuck is secured to the tuning heater opposite to the base member. The tuning heater includes a plurality of zones to fine tune a heat distribution provided by the base member to the chuck.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. Ser. No.13/599,692, which claims the benefit of provisional application Ser.Nos. 61/528,939 filed on Aug. 30, 2011 and 61/635,310 filed on Apr. 19,2012, the contents of which are incorporated herein by reference intheir entirety.

FIELD

The present disclosure relates to heater systems, and in particular,heater systems that can deliver a precise temperature profile to aheating target during operation in order to compensate for heat lossand/or other variations, in such applications as chucks or susceptorsfor use in semiconductor processing.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

In the art of semiconductor processing, for example, a chuck orsusceptor is used to hold a substrate (or wafer) and to provide auniform temperature profile to the substrate during processing.Referring to FIG. 1, a support assembly 10 for an electrostatic chuck isillustrated, which includes the electrostatic chuck 12 with an embeddedelectrode 14, and a heater plate 16 that is bonded to the electrostaticchuck 12 through an adhesive layer 18, which is typically a siliconeadhesive. A heater 20 is secured to the heater plate 16, which may be anetched-foil heater, by way of example. This heater assembly is bonded toa cooling plate 22, again through an adhesive layer 24 that is typicallya silicone adhesive. The substrate 26 is disposed on the electrostaticchuck 12, and the electrode 14 is connected to a voltage source (notshown) such that electrostatic power is generated, which holds thesubstrate 26 in place. A radio frequency (RF) or microwave power source(not shown) may be coupled to the electrostatic chuck 12 within a plasmareactor chamber that surrounds the support assembly 10. The heater 20thus provides requisite heat to maintain temperature on the substrate 26during various in-chamber plasma semiconductor processing steps,including plasma-enhanced film deposition or etch.

During all phases of processing of the substrate 26, it is importantthat the temperature profile of the electrostatic chuck 12 be tightlycontrolled in order to reduce processing variations within the substrate26 being etched, while reducing total processing time. Improved devicesand methods for improving temperature uniformity on the substrate arecontinually desired in the art of semiconductor processing, among otherapplications.

SUMMARY

In one form of the present disclosure, a thermal system includes a basemember including at least one fluid passageway, a tuning heater securedto the base member, and a chuck secured to the tuning heater opposite tothe base member. A two-phase fluid is disposed within the fluidpassageway. A pressure of the two-phase fluid is controlled such thatthe two-phase fluid provides at least one of heating and cooling to thebase member. The tuning heater includes a plurality of zones to finetune a heat distribution provided by the base member to the chuck.

In another form, a thermal system includes: a base member comprising aplurality of fluid passageways in which a two-phase fluid is disposed, apressure of the two-phase fluid being controlled; a tuning heatersecured to the base member and including a plurality of resistiveheating elements; and a chuck secured to the tuning heater opposite thebase member. The tuning heater provides less heat transfer to the chuckthan the base member provides to the chuck such that the base memberprovides a primary heating to the chuck and the tuning heater provides asecondary heating to the chuck. The tuning heater has a number of aplurality of zones greater than a number of the fluid passageways.

In still another form, a thermal system includes: a base membercomprising at least one fluid passageway in which a two-phase fluiddisposed within the fluid passageway, a pressure of the two-phase fluidbeing controlled; a tuning heater secured to the base member anddefining a plurality of heating zones; and a chuck secured to the tuningheater opposite the base member. The tuning heater provides less heattransfer to the chuck than the base member provides to the chuck. Thetuning heater selectively generates different amount of the heat in theplurality of zones depending on a desired heat distribution on the chuckand an actual heat distribution provided by the base member to thecomponent to fine tune the actual heat distribution provided by the basemember to the component.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DRAWINGS

In order that the disclosure may be well understood, there will now bedescribed various forms thereof, given by way of example, referencebeing made to the accompanying drawings, in which:

FIG. 1 is an elevated side view of a prior art electrostatic chuck;

FIG. 2 is a partial side view of a heater having a tuning layer andconstructed in accordance with the principles of one form of the presentdisclosure;

FIG. 3 is an exploded side view of another form of the heater of FIG. 1having a tuning layer or tuning heater and constructed in accordancewith the principles of the present disclosure;

FIG. 4 is a perspective exploded view of the heater of FIG. 3,illustrating an exemplary four (4) zones for the base heater andeighteen (18) zones for the tuning heater in accordance with theprinciples of the present disclosure;

FIG. 5 is a side view of another form of a high definition heater systemhaving a supplemental tuning layer and constructed in accordance withthe principles of the present disclosure;

FIG. 6 is an exploded perspective view of alternating tuning layers thatare offset from one another in accordance with another form of thepresent disclosure;

FIG. 7 is a perspective view of control devices that are embedded intolayers of the heater chuck assembly in accordance with one form of thepresent disclosure;

FIG. 8 is a perspective view of a heater system having independentlycontrollable heater elements constructed in accordance with theprinciples of the present disclosure;

FIG. 9 is a cross-sectional view, taken along line 9-9 of FIG. 8,illustrating vias of the heater system and constructed in accordancewith the principles of the present disclosure;

FIG. 10 is a partial cross-sectional view, taken along line 10-10 ofFIG. 8, illustrating an upper base of the heater system and constructedin accordance with the principles of the present disclosure;

FIG. 11 is a partial cross-sectional view, taken along line 11-11 ofFIG. 8, illustrating a lower base of the heater system and constructedin accordance with the principles of the present disclosure;

FIG. 12 is a top view of FIG. 11, illustrating elements within taperedcavities of the lower base and constructed in accordance with theprinciples of the present disclosure;

FIG. 13 is a cross-sectional view of another form of a high definitionheater system with the base member having fluid passageways for atwo-phase fluid and constructed in accordance with the teachings of thepresent disclosure;

FIG. 14 is a perspective view illustrated a plurality of supportelements constructed in accordance with another form of the presentdisclosure;

FIG. 15 is a cross-sectional view illustrating the support elements inaccordance with the teachings of the present disclosure;

FIG. 16 is an enlarged plan view of a support element in accordance withthe teachings of the present disclosure; and

FIG. 17 is a perspective view illustrating heat spreaders constructed inaccordance with the teachings of the present disclosure.

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses. Forexample, the following forms of the present disclosure are directed tochucks for use in semiconductor processing, and in some instances,electrostatic chucks. However, it should be understood that the heatersand systems provided herein may be employed in a variety of applicationsand are not limited to semiconductor processing applications.

Referring to FIG. 2, one form of the present disclosure is a heater 50that includes a base heater layer 52 having at least one heater circuit54 embedded therein. The base heater layer 52 has at least one aperture56 (or via) formed therethrough for connecting the heater circuit 54 toa power supply (not shown). The base heater layer 52 provides primaryheating while a tuning heater layer 60 disposed proximate the heaterlayer 52 as shown provides for fine tuning of a heat distributionprovided by the heater 50. The tuning layer 60 includes a plurality ofindividual heating elements 62 embedded therein, which are independentlycontrolled. At least one aperture 64 is formed through the tuning layer60 for connecting the plurality of individual heating elements 62 to thepower supply and controller (not shown). As further shown, a routinglayer 66 is disposed between the base heater layer 52 and the tuninglayer 60 and defines an internal cavity 68. A first set of electricalleads 70 connects the heater circuit 54 to the power supply, whichextend through the heater layer aperture 56. A second set of electricalleads 72 connects a plurality of heating elements 62 to the power supplyand extend through the internal cavity 68 of the routing layer 66, inaddition to the aperture 55 in the base heater layer 52. It should beunderstood that the routing layer 66 is optional, and the heater 50could be employed without the routing layer 66 and instead having onlythe base heater layer 52 and the tuning heater layer 60.

In another form, rather than providing fine tuning of a heatdistribution, the tuning layer 60 may alternately be used to measuretemperature in the chuck 12. This form provides for a plurality ofarea-specific or discreet locations, of temperature dependent resistancecircuits. Each of these temperature sensors can be individually read viaa multiplexing switching arrangement, exemplary forms of which are setforth in greater detail below that allows substantially more sensors tobe used relative to the number of signal wires required to measure eachindividual sensor. The temperature sensing feedback can providenecessary information for control decisions, for instance, to control aspecific zone of backside cooling gas pressure to regulate heat fluxfrom the substrate 26 to the chuck 12. This same feedback can also beused to replace or augment temperature sensors installed near the baseheater 50 for temperature control of base heating zones 54 or balancingplate cooling fluid temperature (not shown) via ancillary cool fluidheat exchangers.

In one form, the base heater layer 50 and the tuning heater layer 60 areformed from enclosing heater circuit 54 and tuning layer heatingelements 62 in a polyimide material for medium temperature applications,which are generally below 250° C. Further, the polyimide material may bedoped with materials in order to increase thermal conductivity.

In other forms, the base heater layer 50 and/or the tuning heater layer60 are formed by a layered process, wherein the layer is formed throughapplication or accumulation of a material to a substrate or anotherlayer using processes associated with thick film, thin film, thermalspraying, or sol-gel, among others.

In one form, the base heating circuit 54 is formed from Inconel® and thetuning layer heating elements 62 are a Nickel material. In still anotherform, the tuning layer heating elements 62 are formed of a materialhaving sufficient temperature coefficient of resistance such that theelements function as both heaters and temperature sensors, commonlyreferred to as “two-wire control.” Such heaters and their materials aredisclosed in U.S. Pat. No. 7,196,295 and pending U.S. patent applicationSer. No. 11/475,534, which are commonly assigned with the presentapplication and the disclosures of which are incorporated herein byreference in their entirety.

With the two-wire control, various forms of the present disclosureinclude temperature, power, and/or thermal impedance based control overthe layer heating elements 62 through knowledge or measurement ofvoltage and/or current applied to each of the individual elements in thethermal impedance tuning layer 60, converted to electrical power andresistance through multiplication and division, corresponding in thefirst instance, identically to the heat flux output from each of theseelements and in the second, a known relationship to the elementtemperature. Together these can be used to calculate and monitor thethermal impedance load on each element to allow an operator or controlsystem to detect and compensate for area-specific thermal changes thatmay result from, but are not limited to, physical changes in the chamberor chuck due to use or maintenance, processing errors, and equipmentdegradation. Alternatively, each of the individually controlled heatingelements in the thermal impedance tuning layer 60 can be assigned asetpoint resistance corresponding to the same or different specifictemperatures which then modify or gate the heat flux originating fromcorresponding areas on a substrate through to the base heater layer 52to control the substrate temperature during semiconductor processing.

In one form, the base heater 50 is bonded to a chuck 51, for example, byusing a silicone adhesive or even a pressure sensitive adhesive.Therefore, the heater layer 52 provides primary heating, and the tuninglayer 60 fine tunes, or adjusts, the heating profile such that a uniformor desired temperature profile is provided to the chuck 51, and thus thesubstrate (not shown).

In another form of the present disclosure, the coefficient of thermalexpansion (CTE) of the tuning layer heating elements 62 is matched tothe CTE of the tuning heating layer substrate 60 in order to improvethermal sensitivity of the tuning layer heating elements 62 when exposedto strain loads. Many suitable materials for two-wire control exhibitsimilar characteristics to Resistor Temperature Devices (RTDs),including resistance sensitivity to both temperature and strain.Matching the CTE of the tuning layer heating elements 62 to the tuningheater layer substrate 60 reduces strain on the actual heating element.And as the operating temperatures increase, strain levels tend toincrease, and thus CTE matching becomes more of a factor. In one form,the tuning layer heating elements 62 are a high purity Nickel-Iron alloyhaving a CTE of approximately 15 ppm/° C., and the polyimide materialthat encloses it has a CTE of approximately 16 ppm/° C. In this form,materials that bond the tuning heater layer 60 to the other layersexhibit elastic characteristics that physically decouple the tuningheater layer 60 from other members of the chuck 12. It should beunderstood that other materials with comparable CTEs may also beemployed while remaining within the scope of the present disclosure.

Referring now to FIGS. 3-5, one exemplary form of the heater having botha base heater layer and a tuning layer (as generally set forth above inFIG. 2) is illustrated and generally indicated by reference numeral 80.The heater 80 includes a base plate 82, (also referred to as a coolingplate), which in one form is an Aluminum plate approximately 16 mm inthickness. A base heater 84 is secured to the base plate 82, in one formusing an elastomeric bond layer 86 as shown. The elastomeric bond may beone disclosed in U.S. Pat. No. 6,073,577, which is incorporated hereinby reference in its entirety. A substrate 88 is disposed on top of thebase heater 84 and is an Aluminum material approximately 1 mm inthickness according to one form of the present disclosure. The substrate88 is designed to have a thermal conductivity to dissipate a requisiteamount of power from the base heater 84. Because the base heater 84 hasrelatively high power, without a requisite amount of thermalconductivity, this base heater 84 would leave “witness” marks (from theresistive circuit trace) on adjacent components, thereby reducing theperformance of the overall heater system.

A tuning heater 90 is disposed on top of the substrate 88 and is securedto a chuck 92 using an elastomeric bond layer 94, as set forth above.The chuck 92 in one form is an Aluminum Oxide material having athickness of approximately 2.5 mm. It should be understood that thematerials and dimensions as set forth herein are merely exemplary andthus the present disclosure is not limited to the specific forms as setforth herein. Additionally, the tuning heater 90 has lower power thanthe base heater 84, and as set forth above, the substrate 88 functionsto dissipate power from the base heater 84 such that “witness” marks donot form on the tuning heater 90.

The base heater 84 and the tuning heater 90 are shown in greater detailin FIG. 4, in which an exemplary four (4) zones are shown for the baseheater 84, and eighteen (18) zones for the tuning heater 90. In oneform, the heater 80 is adapted for use with chuck sizes of 450 mm,however, the heater 80 may be employed with larger or smaller chucksizes due to its ability to highly tailor the heat distribution.Additionally, the high definition heater 80 may be employed around aperiphery (shown by area P) of the chuck (across a horizontal plane), oralong a vertical location, FIG. 3, tuning layer 90′, or in discretepredetermined locations across or along the chuck, or around theperiphery other components or combinations of components, rather than ina stacked/planar configuration as illustrated herein. Further still, thehigh definition heater 80 may be employed in process kits, chamberwalls, lids, gas lines, and showerheads, among other components withinsemiconductor processing equipment. It should also be understood thatthe heaters and control systems illustrated and described herein may beemployed in any number of applications, and thus the exemplarysemiconductor heater chuck application should not be construed aslimiting the scope of the present disclosure.

The present disclosure also contemplates that the base heater 84 and thetuning heater 90 not be limited to a heating function. It should beunderstood that one or more of these members, referred to as a “basefunctional layer” and a “tuning layer,” respectively, may alternately bea temperature sensor layer or other functional member while remainingwithin the scope of the present disclosure. Other functions may include,by way of example, a cooling layer or a diagnostic layer that wouldcollect sensor input such as various electrical characteristics, amongothers.

As shown in FIG. 5, a dual tuning capability may be provided with theinclusion of a secondary tuning layer heater 120 on the top surface ofthe chuck 12. The secondary tuning layer may alternately be used as atemperature sensing layer rather than a heating layer while remainingwithin the scope of the present disclosure. Accordingly, any number oftuning layer heaters may be employed and should not be limited to thoseillustrated and described herein.

In another form, the base functional layer may include a plurality ofthermoelectric elements rather than the base heater 84 construction asset forth above. These thermoelectric elements may also be arranged inzones and are generally disposed on top of, or proximate, the base plateor cooling plate 82.

In still another form, the multiple tuning layers may be employed in a“stacked” configuration, or configured vertically such that individualresistive traces are offset from adjacent resistive traces on opposedlayers to compensate for the gaps that exist between traces. Forexample, as shown in FIG. 6, a first tuning layer 130 is offset from asecond tuning layer 140 such that the traces 142 of tuning layer 140 arealigned adjacent the gaps 132 between the traces 134 of the first tuninglayer 130, and vice versa. In another form, a “checkerboard” design maybe employed in order to compensate for gaps or hot spots betweenadjacent layers.

Referring to FIG. 7, the threshold voltage switching circuits, which inone form comprise discrete solid state devices that electrically conductin one direction when the voltage threshold across the circuit isexceeded and which, are embedded into or attached to the body of theheater chuck, which may be in a packaged form or generally embedded asbare die components. In another form, the control elements are embeddedin the bond layer 86 as illustrated above. It should be understood thatthe control elements may be embedded within any of the components orassemblies thereof while remaining within the scope of the presentdisclosure. Alternately, the threshold voltage switching circuits on asingle package silicon controls device (ASIC) may be embedded into orattached to the chuck in one form of the present disclosure. Additionalcontrols devices may also be employed in order to provide redundancyshould any of the components fail during operation.

One exemplary form of embedding controls is illustrated in FIGS. 8-12.As shown, this alternate form of a heater system is illustrated andgenerally indicated by reference numeral 200. The heater system 200comprises a plurality of independently controllable heater elements 202,the operation of which is set forth in greater detail below, in order toprovide a highly tailored temperature profile to a heating target, suchas a uniform temperature profile to a substrate in semiconductorprocessing as set forth above. An upper base 204 is disposed proximatethe heater elements 202, and in one form, the heater elements 202 aredisposed on the upper base 204, such as an etched foil bonded to or alayered heater deposited onto the upper base 204. The upper base 204defines a plurality of tapered cavities 206, which are aligned with eachof the heater elements. The tapered cavities 206 in this form include anupper wall 208 and tapered side walls 210 as shown. The upper base 204further comprises a plurality of power vias 212 in order to provide apassageway for power and control lines, as set forth below.

A lower base 220 is adjacent the upper base 204 and defines a pluralityof reverse tapered cavities 222 aligned with the tapered cavities 206 ofthe upper base 204. The reverse tapered cavities 222 similarly define alower wall 224 and tapered sidewalls 226. The lower base 220 furthercomprises a plurality of power vias 228 in communication with the powervias 212 of the upper base 204, which also serve as passageways forpower and control lines.

As best shown in FIG. 14, the shape of the cavities 206, 222 areconfigured to provide for an efficient transfer of heat from the heaterelements 202 to a cooling plate (shown as element 22 in FIG. 1) and alsoto reduce the thermal impact of the cavities and their components on theperformance and temperature profile provided by the heater elements 202.Accordingly, the “footprint” of the cavity is smaller near the heaterelements 202, and the cavity gradually increases in size to direct theheat flux around the cavity 206, and then gradually decreases in size todirect the heat flux around the cavity 222 towards the cooling plate 22.It should be understood that other geometries for the cavities 206 and222 may be provided by the present disclosure, and thus the taperedconfigurations should not be construed as limiting the scope of thepresent disclosure.

As further shown, a plurality of pairs of switching elements 230 andcontrol elements 232 are disposed within the reverse tapered cavities222 of the lower base 220 and in communication with the plurality ofheater elements 202. Generally, the switching elements 230 and controlelements 232 control operation of the heater elements 202 in order toprovide a requisite temperature profile, and in one application, auniform temperature profile to the substrate in semiconductor processingequipment as set forth above. More specifically, and in one form, thecontrol element is a microprocessor. In another form, the controlelement is a circuit in accordance with the raster boost heater as setforth above. In one form, the control elements 232 communicate across adigital bus 234 for temperature control of the heater elements 202.

The heater system 200 further comprises a multiplexer 240 incommunication with each of the control elements 232, which sends theappropriate control signals to each of the heater elements 202 for adesired temperature profile. In one form, the multiplexer 240communicates with a power supply (not shown) through an optical bus 242.

Additionally, the heater system 200 may also include a plurality ofdiscrete temperature sensors 250 disposed proximate the plurality ofheater elements 202. In an alternate form, the heater elements 202comprise a resistive material having sufficient temperature coefficientof resistance characteristics such that the resistive material functionsas both a heater and a temperature sensor, as set forth herein in otherforms of the present disclosure.

In an electrostatic chuck application, the heater system 200 furthercomprises an RF filter 260, which in one form is in communication with adigital bus 262.

Temperature calibration of any of the systems set forth herein may beperformed by first measuring the individual resistances of the tuninglayer heaters using a standard resistance meter. In another method,alone or in addition to the method above, the tuning layer heaterelements 62 may be held at a constant temperature and pulsed as innormal operation but for short duration only, and then the resistance iscalculated and set into the control system. An iterative technique ofthis at the same or multiple temperature points will calibrate thesystem for control.

Referring now to FIG. 13, another form of a heater system is illustratedand generally indicated by an apparatus 300. The apparatus 300, which isa heater in one form of the present disclosure, includes a base member310 having at least one fluid passageway 320. Multiple fluid passageways320 are illustrated in this form, and the passageways 320 may furtherdefine zones (such as the heater zones as set forth above) in anotherform of the present disclosure. A two-phase fluid 325 is disposed withinthe fluid passageways 320, and a pressure of the two-phase fluid 325 iscontrolled such that the two-phase fluid 325 provides heating to thebase member 310. This system is described in greater detail, forexample, in U.S. Pat. Nos. 7,178,353 and 7,415,835 and also in publishedU.S. application No. 20100076611, the contents of which are incorporatedherein by reference in their entirety. Generally, in these systems,pressurized refrigerant is provided as a condensed liquid and also in agaseous state. The condensed liquid is expanded to a vaporous mix, andthe gaseous refrigerant is added to reach a target temperaturedetermined by its pressure. Temperature corrections can thus be madevery rapidly by gas pressure adjustments. Such systems are provided byAdvanced Thermal Sciences Corporation and may be employed with theteachings of the present disclosure.

As further shown, a tuning layer 330 is secured to the base member 310,for example with an adhesive layer 332, wherein the tuning layer 330comprising a plurality of zones 335. This tuning layer 330 is similar tothe tuning layers and heaters set forth above, and as such, will not bedescribed again in detail for purposes of clarity. Similar to the formsset forth above, the tuning layer 335 has lower power than the basemember 310. And as further shown, a component 340, such as by way ofexample, a chuck, a pedestal, a wafer table, a substrate support, or ashowerhead, is secured to the tuning layer 330. As used herein, a“component” should be construed to mean any member or assembly on whicha wafer is supported, either directly or indirectly, for processing.

In one form, the tuning layer 330 is a heater, and yet in another form,the tuning layer 330 is a temperature sensor, as set forth in detailabove. This tuning layer 330, and also the base member 310, may bedesigned with a material having sufficient TCR characteristics such thatthey function as both a heater and as a temperature sensor.Additionally, a secondary tuning layer (shown in FIG. 5) is secured to atop surface of the component 340, and it should also be understood thatany number of tuning layers, functioning as heaters and/or temperaturesensors, may be employed while remaining within the scope of the presentdisclosure. With the secondary tuning layer secured to the top surfaceof the component 340, the wafer would be supported indirectly, versusdirectly when the wafer is on the top surface of the component 340.

The apparatus 300 may also employ the routing layer 66 as shown in FIG.2 in order to accommodate a number of power lines. Additional featuresas set forth herein throughout the figures may also be employed withthis form of the present disclosure having a base member 310 with fluidpassageways 320 while remaining within the scope of the presentdisclosure.

Referring now to FIGS. 14-16, another form of the present disclosureincludes a plurality of support elements 600 are provided between thetuning heater layer and the boost heater layer in order to provide therequisite flatness during manufacture, which in this form is a pressprocess. More specifically, in this form of the present disclosure, thesupport elements 600 are etched into a copper layer 602 having a heatercircuit. As shown in FIG. 14, relatively large space is present betweentraces in the copper layer 602, which is somewhat of a void thatcontributes to a non-flat laminate, or a laminate that has anundesirable flatness. By providing support elements 600, additionalstructure is provided in order to improve flatness. And as shown in FIG.16, the support elements 600 are in a “split” configuration, or arecomprised of two portions 602 and 604 having an opening 610therebetween. As such, the adhesive 620 (shown in FIG. 15) is allowed toflow more evenly between each of the support elements 600.

As shown in FIG. 17, another form of the tuning heater 700 isillustrated, wherein a corresponding plurality of heat spreaders 710 aredisposed on each of the elements 720 to provide temperature uniformityacross the individual elements 720. The heat spreaders can be a varietyof materials, including but not limited to, Aluminum, Copper, andPyrolytic Graphite, including PGS (Pyrolytic Graphite Sheet). In oneform, the heat spreaders 710 are a monolithic and constant thicknessconfiguration as shown. However, it should be understood that otherconfigurations, including integral grooves, or heat guides, 730 may alsobe provided while remaining within the scope of the present disclosure.

Each of the tuning layers/heaters set forth herein are controlled by acontrol system, various forms of which are set forth in greater detailin co-pending applications titled “System and Method for Controlling aThermal Array,” and applications titled “Thermal Array System,”concurrently filed herewith and commonly assigned with the presentapplication. Generally, the control systems have a plurality of sets ofpower lines in communication with the tuning layer and a plurality ofaddressable control elements in electrical communication with the powerlines and with the tuning layer, the control elements providingselective control of the tuning layer zones. The control elements maybe, by way of example, threshold voltage switching circuits, which maybe semiconductor switches. The threshold voltage switching circuits maybe packaged, for example in an ASIC (Application Specific IntegratedCircuit). Furthermore, the control elements may be embedded within thecomponent, such as the chuck, as set forth above. These control systemsand their related algorithms are described and illustrated in greaterdetail in the co-pending applications set forth above and thus are notincluded herein for purposes of clarity.

It should be noted that the disclosure is not limited to the embodimentsdescribed and illustrated as examples. A large variety of modificationshave been described and more are part of the knowledge of the personskilled in the art. These and further modifications as well as anyreplacement by technical equivalents may be added to the description andfigures, without leaving the scope of the protection of the disclosureand of the present patent.

What is claimed is:
 1. A thermal system comprising: a base memberdefining at least one fluid passageway in which a two-phase fluid isdisposed, a pressure of the two-phase fluid being controlled such thatthe two-phase fluid provides at least one of heating and cooling to thebase member; a tuning heater secured to the base member; and a chucksecured to the tuning heater opposite the base member, wherein thetuning heater comprises a plurality of zones to fine tune a heatdistribution provided by the base member to the chuck.
 2. The thermalsystem according to claim 1, wherein the tuning heater comprises aresistive material with temperature coefficient of resistance (TCR)characteristics such that the tuning heater functions as both a heaterand as a temperature sensor.
 3. The thermal system according to claim 1,wherein the tuning heater defines a layered construction.
 4. The thermalsystem according to claim 1, wherein the tuning heater defines apolyimide heater.
 5. The thermal system according to claim 1 furthercomprising a plurality of tuning heaters defining resistive circuitsthat are offset from resistive circuits of adjacent tuning heaters. 6.The thermal system according to claim 1 further comprising a secondarytuning layer secured to a top surface of the chuck.
 7. The thermalsystem according to claim 1 further comprising a plurality of tuninglayers.
 8. The thermal system according to claim 7, wherein theplurality of tuning layers includes a first tuning layer and a secondtuning layer, the first tuning layer including a plurality of firstheating traces, the second tuning layer including a plurality of secondheating traces, wherein the second heating traces are offset from thefirst heating traces.
 9. The thermal system according to claim 8,wherein the first heating traces define a plurality of gaps betweenadjacent ones of the first heating traces, and wherein the secondheating traces are aligned with the gaps.
 10. The thermal systemaccording to claim 7, wherein the plurality of tuning layers arearranged in a stacked configuration.
 11. The thermal system according toclaim 1, wherein at least one of the fluid passageways and the tuningheater are disposed around a periphery of the chuck.
 12. The thermalsystem according to claim 1 further comprising a plurality of heatspreaders disposed proximate each of the zones of the tuning heater. 13.The thermal system according to claim 11, wherein the heat spreaders area material selected from the group consisting of Aluminum, Copper,Pyrolytic Graphite, and Aluminum Nitride.
 14. The thermal systemaccording to claim 1, wherein the tuning layer comprises a plurality ofresistive heating elements defining the plurality of zones.
 15. Thethermal system according to claim 14, wherein the plurality of resistiveheating elements are independently controllable.
 16. The thermal systemaccording to claim 15, wherein the tuning heater provides less heattransfer to the chuck than the base member provides to the chuck suchthat the base member provides a primary heating to the chuck and thetuning heater provides a secondary heating to the chuck.
 17. The thermalsystem according to claim 16, wherein the tuning heater selectivelygenerates different amount of heat in the plurality of zones dependingon a desired heat distribution on the chuck and an actual heatdistribution provided by the base member to the chuck to fine tune theactual heat distribution provided by the base member to the chuck.
 18. Athermal system comprising: a base member comprising a plurality of fluidpassageways in which a two-phase fluid is disposed, a pressure of thetwo-phase fluid being controlled; a tuning heater secured to the basemember and including a plurality of resistive heating elements; and achuck secured to the tuning heater opposite the base member, wherein thetuning heater provides less heat transfer to the chuck than the basemember provides to the chuck such that the base member provides aprimary heating to the chuck and the tuning heater provides a secondaryheating to the chuck, and wherein the tuning heater has a number of aplurality of zones greater than a number of the fluid passageways. 19.The thermal system according to claim 18, wherein the tuning heatercomprises a plurality of resistive heating elements that areindependently controllable to selectively generate different amount ofthe heat in the plurality of zones depending on a desired heatdistribution on the chuck and an actual heat distribution provided bythe base member to the chuck to fine tune the actual heat distributionprovided by the base member to the component.
 20. A thermal systemcomprising: a base member comprising at least one fluid passageway inwhich a two-phase fluid disposed within the fluid passageway, a pressureof the two-phase fluid being controlled; a tuning heater secured to thebase member and defining a plurality of heating zones; and a chucksecured to the tuning heater opposite the base member, wherein thetuning heater provides less heat transfer to the chuck than the basemember provides to the chuck, the tuning heater selectively generatingdifferent amount of the heat in the plurality of zones depending on adesired heat distribution on the chuck and an actual heat distributionprovided by the base member to the component to fine tune the actualheat distribution provided by the base member to the component.